Lock washer

ABSTRACT

An electrical connector formed with a lock washer portion having a plurality of inwardly extending locking tabs. Each tab is formed into a bent configuration between a punch and die which are so shaped that each tab remains integrally connected throughout its circumferential extent with the body portion of the lock washer section by a bend line with one side edge portion of each tab projecting above and the other below the plane of the body portion of the washer.

United StatesPatent [1113,577,577

[72] Inventor Alfred M. Zak 2,295,583 9/1942 Jordan 10/73 6110 Casrnere Ave., Detroit, Mich. 48212 2,716,247 8/1955 Poupitch 10/73 21 Appl. No. 824,192 3,060,992 10/1962 l-lopp et al. 10/73 [22] Filed May 13, 1969 3,238,543 3/1966 Hopp et a1. 10/73 [45] Patented May4,1971 3,258,796 7/1966 Chiarugi 10/86 Primary Examiner-Richard J. l-lerbst, E. M. Combs Attorney-Bames, Kisselle, Raisch and Choate [54] LOCK WASHER lzclmms 14 Drawing Figs ABSTRACT: An electrical connector formed with a lock [52] U.S.Cl 10/73 washer portion having a plurality of inwardly extending 1 Int-Cl B21153/20 locking tabs. Each tab is formed into a bent configuration [50] Field 01 Search 10/73, 85, b tw n a punch and die which are SO shaped that each tab 36, 36 151/35 remains integrally connected throughout its circumferentialextent with the body portion of the lock washer section by a [56] Relerences Cited bend line with one side edge portion of each tab projecting UNITED STATES PATENTS above and the other below the plane of the body portion of the 1,915,612 6/ 1933 Olson 10/73 washer.

PATENTED MAY 4197:

SHEET 1 OF 3 H6. IO

K A m D E R F I- A ATTORNEY6 PATENIEU MY 4 |97l SHEET 2 OF 3 INVENTOR. ALFRED M. ZAK

BY wwm w M ATTORNEYS PATENTEB MAY man 577- 577 sum 3 or 3 INVENTOR. ALFRED M. ZAK

M, W im- ATTORNEYS 1 LOCK WASHER This invention relates to a-method and apparatus for fonning a lock washer and the product resulting therefrom. More specifically, the invention relates to a lock washer formed as an integral part of an electrical connector.

Conventional lock washers of the type having'a plurality of radially extending locking tabs are normally formed by twisting the tabs to an angular position relative to the plane of the body portion of the washer. In some instances the tabs, after forming, are only partially connected with the body portion of the lock'washer. Conventional tooling employed for forming such lock washersis expensive, subject to considerable wear and provided with metal forming teeth which are relatively fragile. Furthermore, such locking tabs as conventionally formed are relatively weak and fail to establish good electrical connection between the connector and the panel or bus bar to which it is connected.

The present invention has for its object the provision of a lock washer wherein the locking tabs are bent in a manner as to remain integrally connected with the body portion of the lock washer throughout their circumferential extent and, nevertheless, project above and below the plane of the body portion to obtain the desired gripping action and a good electrical connection.

A further object of the invention resides in the provision of a method for forming such locking tabs so that the tooling employed (namely, a punch and die) can be constructed economically with metal forming surfaces thereon which are rigidly backed and subjected to relatively little wear.

In the drawings:

, FIG. 1 is a side elevational view of an electrical connector embodying the lock washer construction of the present invention.

FIG. 2 is a fragmentary plan view of a lock washer according to the present invention.

FIG. 3 is a fragmentary perspective view of a portion of the connector shown in FIG. I and illustrating the configuration of one of the locking tabs.

FIG. 4 is a sectional view along line 4-4 in FIG. 2.

FIG. 5 is a sectional view along line 5-5 in FIG. 2.

FIG. 6 is an end view of the die utilized for forming the lock washer.

FIG. 7 is a view in the direction of arrow 7 in FIG. 2 and showing in broken lines the manner in which the punch and die operate on the tabs of the lock washer.

FIG. 8 shows generally the manner in which the metal forming faces of the punch and die are ground.

FIG. 9 is a fragmentary view in the direction of arrow 9 in FIG. 8.

FIG. It) is a vertical sectional view showing the manner in which the punch and die are arranged relative to one another for shaping the tabs on the lock washer.

FIG. II is a view similar to FIG. 2 and showing a modified form of lock washer.

FIG. 12 is an end view of the die utilized for forming the tab structure shown in FIG. 11.

FIG. I3 is a fragmentary perspective view of a portion of the structure shown in FIG. 11.

FIG. 14 is a sectional view along line 14-14 in FIG. 12.

Referring first to FIG. I, there is illustrated an electrical connector 10 having a wire grip portion 12 at one end inwhich a conductor 14 is adapted to be c'rimpcd to establish an electrical connection between the conductor and the connector. At its opposite end connector 10 is formed with a lock washer portion 16 which is illustrated in greater detail in FIG. 2. Lock washer portion 16 includes a generally flat body portion 18 provided with a central aperture 20. A plurality of radially inwardly extending locking tabs 22 are spaced around the periphery of opening 20. As shown in FIG. 3. each tab is divided generally into three triangularly shaped sections 24, 26 and 28. Section 24 is located on one side of a line 30 which extends from one corner 32 of the tab to generally the midpoint 34 of the circumferential hend line 35 which joins the tab with the body portion of the lock washer.

Section 26 is 24 of each tab 22 located on the opposite side of a line 36 which extends from the other comer 38 of the tab to the midpoint 34. Section 24 inclines upwardly and radially inwardly of the flat body portion 18 while section 26 extends downwardly and radially inwardly of body portion 18. Comer 32 is displaced upwardly relative to the plane of the body portion 18 and corner 38 is displaced downwardly relative to the plane of the body portion 18. It will be observed that sections 24 and 26 are integrally joined to body portion 18 throughout their circumferential extent along bend line 35.

Referring to FIG. 10, the punch and die utilized for forming tabs' 22 as illustrated are shown. The punch is designated 40 and is mounted on an upper die retainer 42 in a bushing 44. Punch 40 is ground with a flat 46 engaged by a set screw 48 extending through bushing 44. The die is designated 50 and is mounted on a lower die retainer 52 in a bushing 54. Die 50 is formed with a flat 56 engaged by a set screw 58 extending through bushing 54. Punch 40 and die 50 are located circumferentially relative to each other by keys 59 in retainers 42,52.

The confronting end faces 60 and 62 of the punch and die, respectively, are similarly shaped and are formed in the same manner. A plan view of face 62 of die 50 is shown in FIG. 6. Face 62 comprises a plurality of V-shaped radially extending grooves 64 which are spaced uniformly around the periphery of the die. The adjacent grooves 64 define teeth 65 therebetween. Grooves 64 are formed in the manner illustrated in FIGS. 8 and 9. Each V-shaped groove 64 is defined by two inclined faces 66 and 68 which intersect at a valley line 70.- Face 68 of one groove intersects face 66 of the. next adjacent groove in a crest line 72. For purposes of description face 66 will be referred to as the working face and face 68 will be referred to as the relief face. As shown in FIGS. 8 and 9, faces 66 and 68 are formed by grinding with a wheel 74 having correspondingly inclined faces around its periphery. In grinding grooves 64 die 50 is inclined to the path of travel of wheel 74 as shown in FIG. 8 so that as the wheel travels across face 62 in grinding a groove 64 it clears the tooth 65 on the diametrically opposite side of the die. This is particularly important where the punch and die are formed with an odd number (as distinguished from an even number) of teeth 65, 65' in their end faces. As shown in FIG. 7 the inclination of face 66 is determined by the degree of flare or twist desired on each locking tab 22. The greater the amount of twist desired, the steeper the angle of faces 66. Relief faces 68 are also inclined to the axis of the die rather than forming these faces parallel to the die axis so that the included angle a at the crest of each tooth is relatively large and, thus, renders the crests 72 relatively strong. It will be observed that, in view of the manner in which grooves 64 are ground, the valley lines '70 incline upwardly in a radially inward direction and the crest lines 72 incline downwardly in a radially inward direction.

Around its outer periphery die 50 is formed with an angularly inclined chamfer 76. Chamfer 76 slopes downwardly in a radially outward direction and forms a plurality of triangularly shaped pads 78 on the radially outer end portion of each tooth 65. The radial extent of each pad 78 corresponds generally to the radial extent of each tab 22 on the lock washer. The circumferential extent of each pad 78 around its outer periphery is approximately one-half the circumferential extent of bend line 35 on each tab 22.

In FIG. 6 the manner in which the body portion 18 of the washer is oriented relative to the die 50 is illustrated. As shown, body portion 18 is located between the punch and die so that the corners 32 of tabs 22 register with the apex 80 of pads 78. Punch 40 is located in its bushing 44 so that when the blank is arranged as shown in FIG. 6 the apices of the triangular pads 78 on the punch register vertically with the corners 38 of tabs 22. It will be observed from FIG. 10 that die 50 projects upwardly beyond the upper end of bushing 54 a slight extent and punch 40 extends downwardly below the lower end of bushing 44 a slight extent. when the punch and die close, tabs 22 are deformed in the manner illustrated in FIG. 3. Section is displaced upwardly by pads 78 on die 50,

. t .3 7 sections 26 of tabs-22 are displaced downwardly by triangular pads 78' on punch 40 and sections 28 are twisted between the working faces 66 and 66' of die 50 and punch 40, respectively. Body portion 18 is maintained flat by bushings, 54 which also form the bend lines 35.

,When the lock washer is arranged on a panel 82 as shown in FIG. 1 with its bottom side contacting the upper side of the panel and is clamped in place by nut 84 on stud 86, the lower portions of corners 38 dig into panel 82 and the upper portions of comers 32 diginto nut 84. Any tendency for theloclt washer to rotate as nut 84 is tightened causes the lower edge portion of comers 38 to scrape the top face of the panel and thus insure good electrical contact between the connector and the panel. This is particularly true in the event that the panel is painted.

- ln FlGS. 11 through 13 a slightly modified form of lock washer and die isillustrated. The only essential difference between the die illustrated in Fl G.6 and that illustrated in FIG. 12 is that in the latter embodiment the generally trianguvlarly shaped pads 88 around the outer periphery of die 90 are formed not by grinding a chamfer butrather by grinding a small radius r around the outer periphery of the die. This radius r is ground so that it is tangent to the sidewall 92 of the die and is also tangent to the flat top face 94 of the die. In other respects die 90 is substantially the same as die 50 and similar members are used to designate the corresponding portions thereof. The punch used with-die 90 is formed to the same contour as the die and is arranged in the same manner as illustrated in FIG. 10.,

When the tabs 96 of the lock washer are formed. between a punch and die shaped as shown in H0. 12, the blank is arranged between the punch and die in the manner previously described. The apex 97 of each pad 88 on the die registers with one corner of each tab 96 and the apex 97- on each pad 88' of the punch registers with the other comer of each tab 96 as shown in FIG. 12. As a result each tab 96 is provided with the configuration shown in FIG. 13. Each tab 96 has three distinct sections 98, 100, 102. Section 98 curves upwardly as at 104 from the plane of body. portion 18 while section 0 curves downwardly as at 106 from the plane of body portion 18. The radially inner edge portions 108 of sections 98 and 100 of tab 96 extend generally horizontally above and below, respectively, the plane of the body portion 18. When a lock washer formed with tabs 96 is arranged on a panel in the manner illustrated in FIG. 1 an excellent scraping action is obtained by reason of the fact that edge portions 1108 contact the top side of the panel and theunderside of the nut throughout a substantial portion of their length and, thus, produce a substantial scraping action on the panel and the nut to insure good electrical contact between the connector and the panel.

Although not illustrated herein, when the connector is blanked by a conventional punch and die a burr is formed along the sheared edges of the blank at one face thereof as is conventional. It is preferred to position the blank between the punch and the die so that the burr on the sheared edges ap pears on the bottom side of the connector; that is, the side which will contact the panel such as shown at 82. This slight burr assists in producing the desirable scraping action of the lock washer tabs against the painted surface of the panel.

From the above description it will be apparent that with a lock washer constructed in accordance with the present invention the locking tabs, although bent such that edge portions thereof are displaced above and below the plane of the body portion of the washer, remain integrally connected to the body portion of the washer throughout their circumferential extent.

Thus the locking tabs are relatively strong because of the bent configuration thereof. in addition, the locking tabs are contoured to provide a good scraping action against the metal surfaces which the locking tabs abut. Furthermore, it will be noted that the punch and die employed for forming the lock washer according to the present invention can be ground economically and to the same contour. The teeth formed thereon are of rigid, relatively heavy construction and are subradial direction. A twist or flare greater than 45 is readily ob- I 'tained with either thin or heavy gauge metal tooling conject to a minimum of wear. The teeth are therefore capable of withstanding substantial impact without chipping or fractur- With the method and apparatus of this invention the amount, of twist or flare that can be imparted to the tabs of the lock washer without shearing or tearing the metal where the tabs connect with the bodyportion is substantially greater than is possible with conventional methods and tooling. This is rendered possible by making the chamfer 76 more steeply inclined or the radius r greater so that the opposite side edge portions of the tab are actually bent a greater extent about bend line 35 as distinguished fromnierely being twisted in a structed in accordance with the present invention.

1 claim: Y

1. Apparatus for making lock washers of the type having a body portion provided with radially extending tabs spaced around the periphery-thereof, said tabs having radially extending side edge portions which are interconnected by a circumferentially extending free edge to form a pair of free corner portions on each tab, said apparatus being adapted to bend the tabs so that one of said side edge portions inclines radially upward from the plane of the body portion and the other inclines radially downwardly from the plane of the body portion, comprising axially opposed punch and die members having similarly contoured metal deforming faces at the confronting ends thereof, each of said end faces having a plurality of generally V-shaped radially extending grooves therein defining metal deforming teeth therebetween, the base of each groove extending radially inwardly in a direction inclined axially outwardly of said end face and the crest of each tooth extending radially inward in a direction axially inwardly 'of said end face, each groove being defined by a pair of radially extending faceseach of which is inclined in a circumferential direction at an acute angle to an axial plane passing through the base of the groove, said teeth being spaced circumferentially apart so as to correspond with the circumferential spacing of the tabs on the lock washer and each having adjacent the radially outer end portion thereof a pad which inclines at least in part radially outwardly and axially inwardly relative to said end face, said punch and die members being positioned circumferentially relative to each other so that when a lock washer blank is positioned therebetween with the tabs lying in the plane of the body portion the pads on the teeth of the punch register axially with one of said side edge portions of each tab and the pads on the teeth of the die register axially with the other side edge portion of each tab.

2. Apparatus as called for in claim 1 wherein the pads have a radial extent corresponding generally to the radial dimension of the tabs on the lock washer.

3. Apparatus as called for in claim 2 wherein said pads are generally triangularly shaped.

4, Apparatus as called for in claim 3 wherein each pad is defined by a pair of side edges which converge radially inwardly toward the axis of the member.

5. Apparatus as called for in claim 4 wherein said pads are dimensioned such that when said blank is positioned therebetween the radially inner apex of each pad on the die re gisters axially with one of said corners of each tab and the radially inner apex of the pad on the punch registers with the other of said corners on each tab.

6. Apparatus as called for in claim 5 wherein the portions of the confronting groove defining faces on the punch and die members which extend circumferentially between successive pads acting on each tab are parallel.

7 Apparatus as called for in claim 2 wherein said pads on the teeth of each member form segments of a conical surface around the outer periphery of the end face on each member.

8. Apparatus as called for in claim '2 wherein said pads on the teeth of each member form segments of a rounded shoulder around the outer periphery of the end face on each member.

9. Apparatus as called for in claim 2 wherein each pad has a radially inner end portion which is generally flat and substantiallyperpendic'ular to the longitudinal axis of the member.

10. Apparatus as called for in claim 9 wherein each pad has a radial outer end portion which extends arcuately from said flat pad portion to the sidewall of the member.

11. Apparatus as called for in claim 10 wherein said arcuate 

1. Apparatus for making lock washers of the type having a body portion provided with radially extending tabs spaced around the periphery thereof, said tabs having radially extending side edge portions which are interconnected by a circumferentially extending free edge to form a pair of free corner portions on each tab, said apparatus being adapted to bend the tabs so that one of said side edge portions inclines radially upward from the plane of the body portion and the other inclines radially downwardly from the plane of the body portion, comprising axially opposed punch and die members having similarly contoured metal deforming faces at the confronting ends thereof, each of said end faces having a plurality of generally V-shaped radially extending grooves therein defining metal deforming teeth therebetween, the base of each groove extending radially inwardly in a direction inclined axially outwardly of said end face and the crest of each tooth extending radially inward in a direction axially inwardly of said end face, each groove being defined by a pair of radially extending faces each of which is inclined in a circumferential direction at an acute angle to an axial plane passing through the base of the groove, said teeth being spaced circumferentially apart so as to correspond with the cirCumferential spacing of the tabs on the lock washer and each having adjacent the radially outer end portion thereof a pad which inclines at least in part radially outwardly and axially inwardly relative to said end face, said punch and die members being positioned circumferentially relative to each other so that when a lock washer blank is positioned therebetween with the tabs lying in the plane of the body portion the pads on the teeth of the punch register axially with one of said side edge portions of each tab and the pads on the teeth of the die register axially with the other side edge portion of each tab.
 2. Apparatus as called for in claim 1 wherein the pads have a radial extent corresponding generally to the radial dimension of the tabs on the lock washer.
 3. Apparatus as called for in claim 2 wherein said pads are generally triangularly shaped.
 4. Apparatus as called for in claim 3 wherein each pad is defined by a pair of side edges which converge radially inwardly toward the axis of the member.
 5. Apparatus as called for in claim 4 wherein said pads are dimensioned such that when said blank is positioned therebetween the radially inner apex of each pad on the die registers axially with one of said corners of each tab and the radially inner apex of the pad on the punch registers with the other of said corners on each tab.
 6. Apparatus as called for in claim 5 wherein the portions of the confronting groove defining faces on the punch and die members which extend circumferentially between successive pads acting on each tab are parallel. 7 Apparatus as called for in claim 2 wherein said pads on the teeth of each member form segments of a conical surface around the outer periphery of the end face on each member.
 8. Apparatus as called for in claim 2 wherein said pads on the teeth of each member form segments of a rounded shoulder around the outer periphery of the end face on each member.
 9. Apparatus as called for in claim 2 wherein each pad has a radially inner end portion which is generally flat and substantially perpendicular to the longitudinal axis of the member.
 10. Apparatus as called for in claim 9 wherein each pad has a radial outer end portion which extends arcuately from said flat pad portion to the sidewall of the member.
 11. Apparatus as called for in claim 10 wherein said arcuate portion is generally tangent to said flat pad portion at one end thereof.
 12. Apparatus as called for in claim 11 wherein the sidewall of the member is generally parallel to its longitudinal axis and said arcuate pad portion is substantially tangent to said sidewall. 